The only add-on that i know of that does this is Reticle Range Which was last updated on 06/29/17
The add-on uses abilities to determine range, certain abilities have certain ranges. Game detects when the target is in range of ability and so does the add-on.
So, slot some abilities with longer ranges. This add-on won't be entirely useful to non-ranged players.
All the green distances are abilities which are in range to be used, all the red are not in range